Hemerocallis (daylilies) produce elegant, usually trumpet-like blooms in summer and are easy to grow in many gardens. Individual flowers are short-lived but each plant produces many flowers, so displays will last for weeks.
Daylilies thrive in well-drained, fertile soil, but tolerate poorer soils and heavy clay. Avoid planting in heavy shade and borders that dry out in summer.
Planting and care
Before planting container-grown daylilies, improve the soil structure and moisture-retention by digging in well-rotted organic matter, such as garden compost or manure. The same materials can also be used as a mulch around existing plants in spring to help conserve moisture.
Where growth is unsatisfactory, apply a general-purpose fertiliser, such as Growmore, in spring at 50-70g per square metre (1½-2oz per square yard).
Daylilies bought in packets
Bare-root daylilies are often sold in packets at garden centres. These can produce good plants, but need more care initially. Check the plants in the packet are firm and you can see buds or small shoots. Avoid those with long pale shoots.
Pot them up, rather than planting directly in the ground, using a peat-free multi-purpose compost and water well. Place pots in a cold frame or cold greenhouse and keep the compost moist.
Once they are growing strongly, plant out, ideally, in spring or autumn.
Pruning and training
Daylilies do not require training or staking and there is no particular need to deadhead after flowering, but this will improve their appearance, and can help reduce infestations of hemerocallis gall midge (see problems below).
The main pest of daylilies is hemerocallis gall midge. The larvae develop in the buds, causing the flowers to distort or fail to open. Other pests that may be encountered include aphids, slugs and snails.
There are no significant disease problems. However, a new rust disease was found on an imported hemerocallis in 2001. Thankfully, it has not been reported in the UK since but remains notifiable. The typical symptoms are numerous yellow or orange pustules, mainly on the lower leaf surface but occasionally on the upper surface or stem.